The present invention relates to circuit arrangements for operating a household appliance, in particular a household appliance for the care of laundry items.
The term household appliance is understood here to mean in particular an electrical device, preferably with an automatic program flow, which can be used to control the household appliance and which preferably comprises a door, like for instance a washing machine, a dryer, a washer-dryer, a dishwasher or a cooking device.
Circuit arrangements of this type for operating household appliances are already known from the prior art. The known circuit arrangements generally include an EMC mains filter, by means of which the public power supply network is protected against interference signals from the household appliance. EMC stands for electromagnetic compatibility. These are in particular interference signals which develop as a result of the brushes powering a rotor of the household appliance. To prevent the propagation of the interference signals into the public power supply network, the EMC network filter usually has a condenser connecting the network plug poles as well as a bleeder resistor connected in parallel thereto. This is needed in order to bleed residual charges in the condenser and thus to prevent an operating person from receiving an electric shock via the network plug poles when the household appliance is switched off. The need for the high-resistance bleeder resistor is associated here with the disadvantage that a power consumption of approximately 70 mW takes place even when the household appliance is switched off.
Moreover, the known circuit arrangements generally include a switched-mode power supply with a power switch, which are usually arranged in a control panel of the household appliance. The arrangement in particular of the network switch in the control panel results in all machine currents firstly being fed to the control panel and being distributed from there via a suitable module. The EMC filter is therefore arranged directly at the network input of the circuit arrangement.
Nowadays, all actuators, in other words the safety-critical consumers, such as for instance a pump, a valve or a motor, are embodied such that they are connected to the public power supply network when the household appliance is switched on. Activation immediately puts these into operation. This is disadvantageous in that in the event of a possible short-circuit to ground, the safety-critical consumers are switched on, although the household appliance itself is switched off.
Household appliances, such as washing machine, dryers or washer-dryers, generally include an electrical contact element for locking a door. This electrical contact element is nowadays used to ensure that a motor and/or a safety-critical consumer can only be powered when the door is locked. Here the motor current is fed via this door contact, thereby being associated with disadvantages in terms of design of the door catch and the cabling.